food nd cars

I'm gathering the parts for the cam swap and have decided to swap out the head gaskets while i'm in there. I honestly don't know much about quench and compression ratio even though i have tried to do some research.
What do i need to know about this process.
I am planning on running the stock heads just refreshed and resurfaced and have been reading about using the .029 impala gaskets.
Questions are what would my CR be? What length pushrods would work? Any additional info so i could get a decent mail order tune would be great or any info that anyone has would be great.
also my cam of choice is LE 224/230 .573/.568.
I understand there are a lot of other factors that come into play but i need to start somewhere.

food nd cars

anyone?

andysc

iTrader: (6)

do a search and you will see alot of information about impala head gaskets on a fbody. It will raise your compression alittle to about 10.9 ish (stock is 10.4). It will also improve your quench, but not as much as when you do a rebuild and have the pistons flush with the top of the engine block. Stock pistons are down in the hole about .30 I think. So quench will be improved, but the added compression is what works for you. These gaskets have been used for years and were one of the first mods for fbodies when they were new. So check it out. I will be doing this exact mod in the next couple of weeks.

hth

andy schuck

food nd cars

will stock pushrod length be fine?

food nd cars

cmon i used search! i just need to know if stock pushrod length will work.

Gojira94

iTrader: (4)

Stock gasket is .046", IIRC. Impala gasket is .027", IIRC. So that's a change of about .019" altogether. If that was a 1:1 change to pushrod length, then no... but it's not quite a 1:1 proposition due to the geometry, but so close as to not be significant. So stock pushrod length of 7.2" will be so close that it won't make a difference. Or have a set made at 7.18"

Somebody stop me if I'm wrong...

litch2004

iTrader: (1)

I did this with .028 gaskets, heads milled .012, ls7 lifters and 1.6rr and my pushrods are 7.0 . But if you are going with a cam and rr you might as well do nsa rr with guide plates and hardened pushrods. In that case it is cheap insurance to measure them out (tool is less than $20) then order correct length. all cars are different once mods are done and its only an educated guess as to your pushrods length. Sure this will set you back a few extra days but at least it will be done right.

food nd cars

**** i didnt account for the heads being milled during resurfacing .. i guess i'll pick up a comp cams PR measuring tool

merim123

iTrader: (11)

pick up some test springs too so you don't end up compressing that lifter and getting a bad reading or use a solid lifter.

food nd cars

if the head is not milled and just cleaned could i use the stock PR length?

merim123

iTrader: (11)

the only way to know for sure is to check. you don't need a special tool if you have the 7.2 already. just do the sharpie method with a test spring.

joelster

The stock pushrod length will be fine if you are simply swapping gaskets. The difference is negligible.

However, in your case you are going with a much more aggressive cam. You should measure and then order a new set of chromoly pushrods for your application. When I swapped to the comp 503 cam, I went with a 7.3" trickflow chromoly set. I was also running some aftermarket rockers which can effect the pushrod length needed. Pushrods are dirt cheap, even for real good ones. No point in skimping on them.